Tensioning device



July 29, 1941. Gf P. VLEssM/mm l 2,250,540

TENSIONING DEVICE v Filed Jan. 26, 1959 5 sheets-sheetg WITN ESS ES :A *I

INVENTOR l ATTORNE July 29, l941 G. P. LEsSMANN l TENSIONING DEVICE Filed Jan. 26, 1939 3 Sheets-Sheet 5 mvENToR Ger/mrd P g55/72mm.

WITNESSES:

Patented July 29, '1941;

UNITD STATES PATENT 'f 'rENsioNiNG nEvicE Gerhard P. Lessmann, Forest Hills, Pa., assigner to Westinghouse Electric & Manufacturing Company, East Pittsburg Pennsylvania h,la.,acorp oration of Y i, Application January 26,1939, senaiNo.-2sz ,934 'n 12 claims. (ci. so f35) My invention relates, generally, to tensioning devices and, more particularly, to devices for subjecting a strip of material to tension as it passes between adjacent work devices.

It has been f ounddesirable and has become common practice to subject steel strip to tension as it is passing through the reducing rolls of a strip rolling mill. This tensioning of the strip provides a drawing action in addition to the usual rolling action in the reducing rolls and thus produces a greater percentage reduction in each roll stand than is possible by the rolling action alone. In addition,V the drawingA action strip of uniform gauge is to be produced, sudden changes in stripthickness and hardness-maybe compensated for bycOrreSponding/changes'in strip tension, thus. providing whatever tensions are required to reducethe partsfof the strip of varying thickness and hardness toa lpre deter...y

resulting from tensioning the strip as itis rolled imparts certain desirable physical characteristics to the strip steel produced.

Since a very considerable proportion of the reduction' of the strip at each roll stand is due to the tension to which the strip is subjected and the amount of reduction due to tension is a function of the amount of tension, it is apparent that, all otherfactors being equal, the tension should be kept substantially constantv to produce strip of uniform gauge.

Several methods of maintaining a substantial- `ly constant tension on the strip as it-v passes through the mill have been proposed, one such 'method maintaining the tension by current regulation of the .mill motors to maintain a lconstant motor torque. A very successful system for `maintaining a. substantiallyconstant strip tension is fully described in my copending application Serial No. 133,419, iiled March 27, 1937, now Patent No. 2,189,609, issued February 6, 1940.

In the system of my patent an idling roller is strip. Considerable strip .breakage occurs due tothis cause in rolling systems in which the strip is not looped between roll stands.

It has been found that there is a considerable variation in the thickness of the strip throughout lits length as .it is`delivered to be rolled in thestrip mill and that slight variations in the composition of the steel will cause variations inv hardness throughout the length of the strip.

Since the amount of strip reduction is a func' .of different diameters.

mined gauge. 4 An object of mviinvention.' therefore,fis to ,provide a tensioningdevice for-astrip rolling mill which shall function to vary the l tension on i ition ofA the strip tension,l it 'follows/that, if a the strip in accordance with variationstiny the resistance-to-reduction properties ofthe strip@ Another` object; .of the invention @is ,.to, provide a tensioning device for a stripfrolling lmill which shall function Ito provide strip tensions varying in accordance with the resistanceetoreduction properties of the strip and shall have adjustable means 4forproducing the. desired tenA sion characteristics `for a wide variety of strip thicknesses, widths and degrees of hardness.

A further object'ofl the yinvention isv to pro- V Y vide a strip tensioning device of the type which defiectsv the strip by the application of a transverse force thereto with` adjustable meansf for g selectively varying' kthe tension-deflection `criar-- acteristic of the device..

Another object of the vinvention is to provide a tension device, having a strip deiiecting memben-with means for selectively varying the no'rmal range of deiiection ofthe strip. y Still another object of the invention is to pro vide a tensioning device, having a strip deflecting member actuated by a lever, with means for varying the length and the normal placement of the lever arms.

A further object of the invention is to provide tensioning device, having a pivoted lever actu.` ated strip deflecting member, with means for selectively positioning the center of gravity of the actuating mechanism to thus vary the tension deflection characteristic of the device.

A further object of the invention is to provide angular disa tensioning device, having a strip deecting 5 member, with means for raising and lowering-` the normal range of operation of the` deecting-a;

member to compensate for the shifting of the."

reducing rolls -pass line due to the substitution of invention will be apparent from the following 4dv tailed description taken in connection withft accompanying d rawings in.which.'

Figure 1 is a perspective ,view'of a device embodying the principal features of the preferred embodimentl of my invention;

Fig. 2 is a perspective view `of an embodiment .of the invention in which a different form of elevating mechanism for the tensioning device is employed;

Fig. 3 is a diagrammatic illustration of the relative positions of the tensioning device and the strip passing between adjacent roll stands;

Fig. 4 is a graph illustrating the operating characteristics of the tensioning device.

In carrying out the preferred embodiment of my invention shown in Figure 1, I provide a shaft I8 rotatably mounted upon-and extending parallel to a beam member I which is supported between the opposing mill housings I2 and I3 of a strip rolling mill. The beam member which comprises an angle iron having horizontal and vertical flanges is secured to the mill housings I2 and I3 by means of bolts |4 vscrew-threaded into the mill housings through slotted openings |6 in the vertical flange of the beam.

An actuating mechanism |8 is provided for imparting rotational movementito the shaft I8 An idling roller 28 extends between and is rotatably mounted upon parallel arms 22 and 24 which are secured to the shaft |8 by an adjustable coupling 26 by means of which the relative angular displacement of the arms 22 and 24 with respect to the shaft. I8 may be varied. An adjusting mechanism 28 is provided for moving the roller 28 lengthwise of the arms 22 and 24 tothus vary its ldisplacement from the shaft I8.

A pair of jacks38 and 32 are provided for simultaneous operation actuable by the adjusting mechanism 34 for raising or lowering the beam member v|| upon Vwhich the entire tensioning mechanism is mounted.

A pair of shiftable weight members 36 and 38 is provided for varying the center of gravity of the mechanism .to provide variations in the operating characteristics of the tensioning device.

A. regulator control unit comprising a vsynchrotie transmitter 48 by which a remotely positioned regulator for the mill motors is actuated after the manner described in detail in the copending application of W. G. Cook Serial No. 165,287 led September-23, 1937, now Patent No. 2,242,346,

i issued May 20, 1941, and having a common assignee with the present application, is mounted upon the horizontal flange of the beam II. The synchro-tie transmitter 46 is connected to be actuated by the shaft I8 through a clutch mechanism, indicated, so that the relative angular displacement between the synchro-tie mechanism and the regulator actuated thereby and the shaft I8 may be varied.

The embodiment of the invention shown in Fig. 2 is similar to that of Fig. 1 except in the manner of mounting the mechanism in operative position and similar reference characters designate corresponding parts of the two embodiments of the invention. The tensioning mechanism in 'this embodiment of the' invention is hingedly mounted, as shown, upon upright members 42and 44 which are supported by auxiliary -in Fig. 2.

grammatically the relative positions of some of the operating parts of the tensioning mechanism with respect to the strip as it passes between adjacent roll stands.

Referring to Fig. l for a more detailed description of the preferred embodiment of my invention, the shaft I8 is supported by bearing members 58 and 52 which are mounted upon the horizontal flange 54 of the beam II. The operating mechanism I8 for the shaft I8 comprises a lever arm 56 which is secured to the shaft and extends substantially horizontally therefrom. A roller member 58 is rotatably secured to the end of the arm 56 and is positioned between the spaced horizontally disposed ends of an opening in a collar member 68. The upper end of the opening in the collar member 60 is connected by means of a piston rod 62 to an actuatingcylinder 64 similar to that described in my hereinbefore referred to patent. The lower end `of the opening in the collar member 68 is connected by a piston rod 66 to a suitable damping cylinder 68 which is provided .for preventing too sudden movements of the tensioning mechanism.

rihe piston rods 62 and 66 andthe collar member 68 may be constructed integrally or may be made separately and rigidly secured together in any suitable manner as a unitary rod extending between pistons not shown, operating in the cyl-v inders 64 and 68. The rods 62 and 66 are suitably guided between rolier members 61 best shown The actuating cylinder 64 and the damping cylinder 68 are mounted upon a plate member 18 which is suitably secured to the beam memberl I and extends substantially normally therefrom. l

A/sleeve member 12 is rotatably mounted upon the shaft I8 upon the bearing members 58 and 52, and has the crank arm means or members 22 and 24 secured thereto in any suitable manner and extending substantially normally therefrom. The coupling means 26 comprises a bracket 14 secured to the arm 22 and rotatably supporting a worm 16 which cooperates with a worm gear segment 18 secured to the shaft I8. The worm 16 may be actuated by a handwheel 88 to thereby rotate the sleeve 12 and the tensioning roller` supported thereby with respect to the shaft I8.

The tensioning roller 20 is supported in a bearing member 82 which is slidable in a slot as shown in the arm 22 and a similar bearing memf ber, not shown, in the arm 24. Plate members -83 and 84 are secured to the ends of the arms 22 and 24 to limit the movement of the tensioning roller bearings on the arms 22 and 24. A screw member 85 threadedly engages a worm wheel 86 and bears against thebearing member 82 to provide longitudinal movement of the bearing 82 upon rotation of the worm wheel 86. 'I'he bearing vsupporting the other end of the roller 28 in the y has an operating handwheel |88 mounted upon beam members 46 and 48 which extend between the opposing mill housings of adjacent milll stands of the strip mill. 'I'he vertical adjustment of the mechanism is provided by screws 38' and 32 which are screw-threaded into a lower Aiiange of a beam member upon which the mechanism is mounted and engage the auxiliary beams 46 and 48.

In Fig. 3 of the drawings there is shown diaone end thereof. It will be seen that actuation of the handwheel |88 will thus cause longitudinal movement of the roller member 28 in its supporting arms 22 and 24. l

The weight members 36 and 38 are mounted upon arms |82 and |84, respectively. The arm |82 extends substantially vertically downward from the lever arm 56 and the arm |84 extends substantially horizontally from and in the 0D- A shaft 98 extends posite direction to the lever arm 66. Suitable adjusting means are provided for adiustably po sitioning the weights -66 and 38\at any desired point along their supporting arms`\|02 and |84.

When it is desired to adjust the relative posi- 3 to patent to W. G. coole with the arms n, u

' Vmaking an angleoi substantially 51, with'the tions of the shaft |'0 and the' regulating means The .lacks 30 and 32 comprise base members |08 and ||0 supported on suitable bracket members ||2 and |'|4 on the mill housings |2 and i3 andscrew-threaded shafts ||8 and |18 vilxecl to these base members |08 and ||0,'respectively. Worm `gears and |22 are threadedly engaged with\the shafts |`|6 and ||8 and bear against plate members |24 and |26 which in turn engage pla'te members |28 and |30 mounted upon the horizontal flange 54 of the beam Worms |32 and |34 are mounted for rotation on brackets |36 and |38 secured to the plate members |28 and |30. Ashaft |40 `operable by a handwheel |42 is connected to simultaneously actuate the worms |32 and |34. Thus, to adjust the vertical displacement of the entire mechanism, the bolts I4 may be loosened to -permit freedom of move ment of the beam and the handwheel |42l actuated to provide the desired adjustment of the. mechanism. When the `desired adjustment has been made, the bolts |4 may be tightened to secure the mechanismin the desired position.

-Referring to Fig. 2, a plate member |'44 is'secured to the (beam and -arms |46 and |48 aresecured in any suitable mannerjto the plate members 'i0 and |44, respectively, and extend substantially lhorizontally therefromas shown. The arms |46 and |48 are suitably pivoted on the upright arms 42 and 44. The screws 30' and 32' extending through the bottom flange |50 of the beam are held in position bythe lock nuts |62 and |54 and bear against the auxiliary beams 48 and 48 to hold the tensioning mechanism in position. When it is desired to change the vertical displacement of the'tensioning mechanism,

it is only necessary to loosen the lock nuts |62 and |54, actuate the screws 30' and 32'l to raise or lower the beam as desired and to tighten the lock nuts |52 and |54 when the desired adjustment has been made. The part of the beam supporting the clutch mechanism and the synchro-tle transmitter discussed in connection with the embodiment of the invention shown in Fig. 1 has been broken away in Fig. 2 to better illus-v trate the mechanism of Fig. 2.

In the operation of the device, the actuating cylinder 64 will operate upon the arm 66 and transmit through the arms 22 and 24 to the tensionV roller 20 a force which wili-deect the strip from its normal passline between the adjacent roll stands as indicated diagrammatically in Fig. 3. In Fig. 3 the tensioning roll 20 is shown in the normal strip tensioning position and inthe extreme upper and lower positions of its operating range. Tensioning roller 20 may be kept within this operating range by .regulating devices controlled by the synchro-tie transmitter 40 shown in Fig. 1 which regulating -devices may take the form shown in either my hereinbefore referred to patent orr the hereinbefore referred 75.

' extension ofthe lever arm 58 vand a substantially 4constant pressure applied to the arm 66 by the` operating cylinder 84, .a substantially constant tension will be applied to the strip by the tensioning roller 20 as described in my hereinbefore referred to copending application.

I'he curve A of. Fig. 4 illustrates the functioning of the device under these conditions. With the range of deflection above the pass linev between 3V2 inches and 5% inches indicated by the points' M and N on-the curve, it will be seen that there is very little variation inlstrip tension throughout this range of strip deflection. This operation is suitable Where the strip is of uniform. thickness and hardness, and uniform constant tension on the strip will produce a uniform thickness .of finished product.

However, some of the strip material l it'.

comes through the mill may have thick portions and/or relatively hard and soft portions-requiring greater or less degrees i tension to produce the different degrees of reduction necessary in such 'sections of the strip which will result in a uniform' final strip thickness. When a hard section or-a thick section' comes through the mill, for instance, since the degree of .reduction of the strip is a function of .the amount of tension upon the strip, it is desirable 'to increase the tension on the strip. As thevhard section or thick section comes through the mill there 'will be less reduction in the reducing rolls and the amount of strip between adjacentrollstands vwill be less thus decreasing the deectionv of the strip by the tensioning roll 20. Where these conditions exist. it is desirable therefore deflection characteristic which will give arising tension in response to decreased deflection of the strip. This characteristic is produced by actuating the angle adjusting coupling 28 by operathe operation handle 80 as hereinbefore tion of described to decrease the angle between the arms r22 and 24 and extension of the arm 56,'that is.

decrease" the angle between the arms `22 and 24 and thenormal pass line. With` this decrease ln the operating angle of the arms 22- and 24. it will Y be necessary to lower the mechanism if it is desired that the tension roller. 20 operate within the same deection range. This may be done by the actuation as hereinbefore described of the lacks 30 and 32 in the device of Fig. 1 and the screws 30' and 32' in the device ofFlg.` 2.

The tension-deflection characteristic of the de- I vice when the tensioning roll arm angle has been decreased is illustrated by the curve B o! Fig. 4.

It will be seen by reference to this curve that when a hard section of the strip is encountered', the decreased deection 'caused thereby will re.- sult in increased tension in the' strip, to thus produce the necessary increased'strip reducing force necessary to If it is desired tension-deflection characteristic curve of the device, it is only necessary to ment of the tensioning roll 20 from the shaft |8 produce strip of uniform gauge.

- by operation of the handwheel |00 to actuate the adjustingn mechanism 28 as vhereinbefore lvdescribed. Thus by shortening the distance between the tensioning roller 2'0 andthe shaft |0, thereby makingvthe eilective'angle arm of the arms 22 and 24 shorter, a tension-deflection character-A istic curve-indicatedby curve. C of Fig-4 produced. It will be seen tha-t aslightly higherl tension throughout will b e produced by this to have a strip tensionto varyv the atness ofthe vary the displacechange in the tensioning roller lever arm length and that a slightly rising tension characteristic will be produced at the extreme limits of the deflection range. Here again the vertical displacement of the actuating mechanism will have to be changed if the same range of deflection is desired. Y

The atness ofthe tension-d'eiiection characteristic curve may also be controlled by the horizontal adjustment of the: weight 38 on its supporting arm H14. Thus by moving the weight 38 away from the shaft I0 the flatness of the characteristic curve is increased as illustrated by curve D in Fig. 4. By'moving the Weight 38 to the right, the center of gravity of the whole mechanism is moved to the right and va part of the force exerted by means of the actuating cylinder 64 will have to be used in overcoming'the increased torque applied to the system by the movement of the weight 38 further from the axis of rotation of the tensioning device. Thus a smaller actuating force will be applied to the tensioning roller 20 and decreased .tension throughout the tensioning range willbe produced as indicated by curve D.

A change in the tension-deflection characteristic curve similar to that caused by the decrease in the tensioning roll actuating arm angle may be produced by an increased downward displacement of the weight 36 on its supporting arm |02.

'It will be seen that the weight 36 adds to the effective tensioning torques applied to the tension roll 20 when the strip is below its normal position, since the weight 36 will then have moved in a clockwise direction, as viewed in Fig. 3, and will add to the turning l movements acting upon the tensioning roller 20 to deflect the strip. When the tension roll 2U is above its normal position, however, the weight 36 will be moved in a counterclockwise direction and4 will apply a turning mo- .ment to the tensioning system opposite to the moment caused by the pressure applied thru the actuating; cylinder 64 and will thus detract from the effective strip tension in the increased strip deilection range. This effect of mov'ing the weight 36 downward isillustrated by curve E of Fig. 4. Here it will be seen that between the extremes M and N of the range of deflection there will be a rising tension characteristic, the tensioning characteristic being raised at the lower .deflections and lowered at the higher deflections.

The vertical adjustment of the tensioning mechanism is also necessary in the event of changing of reducing rolls in the mills and substituting rolls of greater or less diameter. It will be seen that vthis will raise or lower the normal pass line of the mill and will be necessary to raise or lower the tensioning mechanism a corresponding amount if the same range of deflection above the normal pass line is to be maintained. If it be desired that a rising tension-deflection characteristic curve be provided, the tension range may be shifted by varying the angular displacement of the synchro-tie transmitter 40 with respect to the shaft I as hereinbefore described. Thus, by proper adjustmentof the synchro-tie transmitter, the tensioning roll may be kept within the deflection range of from 2 to 4 inches above the normal pass line and the tension-deflection characteristic will then be that indicated be. rolled. A thicker, wider4 or harder strip will require highertensions. To provide the higher tension range, the range of deflection may be changed from 3.5-5.5 inches indicated by the points M-N, with the tensioning device other- Wise adjusted for the characteristics indicated by curve E,to a range 2.5-4.5 inches indicated by the points O-P.

A similar change in tension range for the purpose of providing the desired tension range for different degrees of strip thickness, width and hardness may be made by changing the tensiohing roll arm angle as explained hereinbefore.

Thus, if the tension-deflection characteristic indicated by curve B includes a greater ten-sion range than is desired for-the particular strip to be rolled, a characteristic illustrated by ,curve B' may be produced by operating the roller arm. "angle adjusting mechanism 26 to give a larger roller arm angle than that which will give the characteristic illustrated by curve B. It will be seen that the rtension range between the points M-N on curve B is smaller than the tension range between these points on curve B.

'I'his same variation of tension range of rising tension characteristic may be produced by variation of the position of the weight 36 as hereinbefore explained and illustrated by curve E. It

may also be produced by varying the "fiatness of the curves by adjustment of the tensioning roller arm length as explained hereinbefore and illustrated by curves C, or by adjusting fthe position of the weight 38 as explained hereinbefore and illustrated by curve D. 'I'he desired rising tension-deflection characteristic would be obtained in these two cases by operating the tensioning roller in the lower deiiection ranges such as, for instance, between the points O--P representing a deflection range of 2.5-4.5 inches.

position of the tensioning roller 20' in Fig. 3.

When the tensioning roller occupies a position substantially equally spaced from the roll stands,

as indicated by the position of the roller 20 in Fig. 3, the reaction on the roller will be substantially vertical as indicated by the vector R.

' If, now, the tensioning device is moved tothe by the curve A between these two deflection ferent ten-sion ranges for different materials to position indicated by the roller 2 0', the reaction on fthe roller will be in the Vdirection indicated -by the vector R', displaced somewhat from the vertical. If this new roller posit-ion is established by merely shifting the whole tensioning mechanism to the left without varying its verltical elevation, roller arm length or roller arm angle, this change in the angle of the reaction on the tensioning roller will have the eilect oi' decreasing the tensioning roller arm angle with respect to the pass line, thus giving the tensioning device a rising :tension-deflection characteristic as indicated by curve B of Fig. 4.

This horizontal adjustment of the tensioning device may most easiily be made with the embodiment of the invention of Fig. 2. Additional threaded holes 45 may be provided in the auxiliary beams 46 and 48 for receiving the screws 41 which secure the upright members 42 and 44 to the auxiliary beams 46 and 48. Thus to provide a rising tension-deflection characteristic for the is to be understood, however, that the invention 3,250,540 move the device to the position wherel the is not limited to the precise constructions shown and described, but is capable of modification ,by one skilled in the artt, the embodiments herein shown being merely illustrative of the principles of my invention.A Y

I claim as my invention:

.1. In a strip tensioning device .for a strip rolling mill, a pivotally mounted lever, a bearing member mounted onone arm oi.'l said lever, means for applying a force to the other arm of said lever to cause said bearing member to transmit a transverse force to 'the strip to thereby deflect the strip and subject it -to tension, and means for selectively varying the angular displacement between said lever arms to thereby vary the tensiondeilection characteristics of the tensioning device.

2. In a strip tensioning device for a strip rolling mill, a pivotally mounted lever, a bearing member mounted on one arm of said lever, means for applying a force to the otherarm of said lever` to cause said bearing member to transmit a transverse force to the strip to thereby deflect the strip and subject it to tension, and means for selectively varying the length of the lever arm upon which said bearing member is mounted to thereby vary the tension-deflection characteristics of the tensioning device.

3. In a strip tensioning system for a strip rolling lmill in which a bearing member subjects the strip to tension by deflecting the strip from its normal passline and is kept within a limited deflection range by a regulator. a regulator control unit, couplingl means for connecting said regulator control unit for actuation in accordance ing saidl arm means for rotation with said shaft, -a roller member mounted onvsaidcrank arm means for rotation about an axis substantiallyparallel with said shaft, means for applying a rotational force to said shaft, means mounting said beam in such a position as to cause said roller to bear against the strip` as it extends between adjacent roll stands to thus subject the strip to tension by deilecting it from its normal pass line, and means for selecively varying the 1 `displacement of said beam with respect to the normal pass line of the strip to thus selectively vary the tension-deflection characteristics of the tensioning device.

6. In a strip tensioning device for a strip rolling mill, a beam member extending normal to the directions: travez of the strip, a shaft mounted for rotation on and substantially parallel with -said beam, crank arm means extending from and substantially normal to said shaft, means securing said crank arm means for rotation with said l. shaft, a rollerr member mounted on said crank arm means for rotation about "an axis substan- :tially parallel with said shaft, means for applying roller to bear against the strip as 'it extends between adjacent roll stands to thus subject the strip to tension by deiiecting it from its normal from, and in a horizontal plane with the axis of a rotational force to said shaft, means mounting said beam in such a position as :to cause said pass line, means for pivotally mounting said .beam onlan axis substantially parallel to, spaced said roller, and means for rotating vsaid'beam with the deflection of the strip by the bearing vmember, `and means whereby the relative .dis-

Vplacement'. of said regulator control unit 'and the bearing member may be selectively varied to thereby selectively vary the limits of the regulator-controlled deflection range. t

about its pivotal axis thus varying the tensiondefiection characteristics of. the tensioning device.

'L/In a strip tensioning device for a strip rolling mill, a. beam member extending normal to' the direction of-travel of the strip, a shaft mounted for rotation on and substantially parallel with said beam, crank arm means extending from and substantially normal to said shaft, means securing said'crank arm means for rotation with said shaft, a roller member mounted on said crank arm means for rotation about an axis substantially parallel with said shaft, means for applying a rotational force to said shaft, means mounting l said beam'in such a position as to cause said roller to bear against the strip as it extends between adjacent roll stands to thus subject the strip to tension-by `deilecting it from its normal pass line, an auxiliary beam extending from each of 4. In a strip tensioning device for a strip rolling mill, a pivotally mounted lever, a bearing member mounted on one arm of said lever and means for applying a force tothe other arm of said lever to cause said bearing member to transmit a transverse force to the strip to thereby deflect the strip and subject it to tension, said means for applying a force to said arm comprising a collar member having an opening therein, a roller member mounted on said other arm of .the opposing mill housings-of one mill stand to the adjacent opposingmill housings of its adjacent mill. stand, means for pivotally mounting said first mentioned beam on said auxiliarybeams on an axis substantially parallel to, spaced from, and substantially in a horizontal plane with the axis of said roller, and means for adjustably positioning said ilrst mentioned beam about its said lever and extending into and operably engaging the ends of the opening in said collar member, a piston rod rigidly secured to said collar membenan actuating piston and cylinder for said piston rbd' and guide means line motion for said piston rod.

. 5*; Iii a. strip tensioning device for a strip rolllng mill, a beam member extending normal to the direction of travel of the strip," a shaft mounted for rotation on and substantially parallel with -said beam, crank arm means extending from and providing straight substantially normal to said shaft, means secur.-

pivotal axis thus varying the tension-deection n characteristics of the tensioning device.

8. In a tensioning mechanism for a strip roll- -ing mill,'a shaft mounted for rotation-and disposed normal to the direction of .travel of the strip as it passes between adjacent roll stands, spaced parallel 'arms disposed substantially normal to said shaft, means securing said arms for rotation with said shaft, a tensioning roller extending between and rotatably supported by said arms, said arms being so disposed as tocause said roller to subject the strip to tension by bearing against the strip and deilecting it when rotating torque is applied to said shaftpa lever arm secured to said shaft and extending substantially normal theretol means for applying a force to torque for said tensioning roller, a pair of auxiliary arms one extending substantially vertically and the other extending substantially horizontally from said shaft and a longitudinally adjust- `able weight Amounted on each of said auxiliary arms whereby the position of the center of gravity of the tensioning mechanism may be shifted any desired amount in any radial direction to thus vary the tension-deflection characteristics of thetensioning mechanism.

9. In a strip tensioning device for a strip rolling mill, a shaft disposed normal to the direction of the pass line of the mill, operating means for.

applying a torque to said shaft, a pair of arms extending away from atsubstantially right angles to said shaft, means securing said arms for rotation with said shaft including means for selectively varying the angulardisplacement of said arms with respect to said shaft, a roller extending between and supported by said arms, means for selectively varying the position of support of said roller on said arms, and means for simultaneously varying the displacement of said shaft,

arms, tensioning roller and operating means from the pass line of the mill `to therebyv vary the tension-deflection characteristics of the tensioning device.

10. In a strip tensioning device for a strip rolling mill, a beam member extending normal to the path of travel of the strip, a shaft mounted for rotation on and substantially parallel with said beam, a sleeve member mounted upon said shaft and coaxial therewith spaced parallel arms secured to and extending from said sleeve member substantially normal to the axis of the sleeve member, a roller extending between and rotatably mounted upon said arms", means connecting said sleeve for rotation with said shaft, said beams being so mounted with respect to the strip and 2,250,540 said lever arm to thus provide the actuating said sleeve having such a relation to said shaft as to cause said roller to subject the strip to tension by bearing upon and deflecting the strip when a rotating force is applied to said shaft, said means connecting said sleeve for rotation with said shaft comprising means for selectively 'varying the relative displacement of said shaft and said sleeve about-their common axis to thereby selectively vary the tension-deflection characteristics of the tensioning device.

1l. In a strip tensioning device for a strip rolling mill, a bearingrnember, an actuating mechanism for the bearing member comprising force providing means and a force transmitting linkage connecting the force providing means in operative relation with the bearing member for causing the bearing member to bear against the strip to thus subject the strip to tension by applying a transverse force to the strip and thereby deflecting the strip from its normal pass line, and means for simultaneously selectively shifting the position of said bearing member and said actuating mechanism relative to the normal pass line of the strip to thereby vary the tensiondeflection characteristics of the tensioning device.

l2. In a strip tensioning device for a strip rolling mill disposed between adjacent roll stands of the mill, a pivotally mounted lever, a bearing member mounted on one arm of said lever, a force providing means disposed to apply a force to the other arm of said lever to cause said bearing member to transmit a transverse force to the strip and thus subject the strip to tension, and means for simultaneously varying the horizontal spacing of the lever, the bearing member, andthe force providing means with respect to the adjacent roll stands to thereby vary the tensiondeflectio'n characteristics of the tensioning device.

GERHARD P. LESSMANN. 

